Source : Webster's Revised Unabridged Dictionary (1913)

Internationalist \In`ter*na"tion*al*ist\, n.
   1. One who is versed in the principles of international law.

   2. A member of the International; one who believes in, or
      advocates the doctrines of, the International.

Source : WordNet®

internationalist
     adj : influenced by or advocating internationalism [syn: {internationalistic}]

internationalist
     n 1: an advocate of internationalism
     2: a member of a socialist or communist international